Leak sensor for flowing electrolyte batteries

ABSTRACT

A leak detection system for a flowing electrolyte battery comprising a containment member associated with at least one of a stack of a flowing electrolyte battery and an electrolyte reservoir of a flowing electrolyte battery and a sensing member for sensing a fluid leak within the containment member.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The invention is directed to flowing electrolyte batteries, andin particular to a leak sensor for use in association with flowingelectrolyte batteries such as zinc/bromine batteries. It will beunderstood that the application is not limited to any zinc/brominebatteries or to any other particular flowing electrolyte battery.

[0003] 2. Background Art

[0004] Flowing electrolyte batteries (Zn—Br batteries, V-Redoxbatteries, etc) are well known in the art for their quality powerproviding characteristics and their cycling ability. Generally, suchbatteries rely on the circulation, by pumps, of electrolyte. As thecirculation of electrolyte includes a multitude of components, fittingsand conduit, a potential always exists for failure of one of thesecomponents. Such failure will generally result a leak of electrolyte.

[0005] In addition, since many such batteries require cooling systemswhich likewise comprise a multitude of conduit, fittings and component,the cooling systems are likewise problematic. Failure in such componentsgenerally results in a leak of coolant. Further still, many suchbatteries, especially in industrial applications, are placed in asubstantially sealed container which is remains exposed to a harshenvironments. As such, damage to the sealed container often results inthe collection of precipitation within the container.

[0006] Any leak of electrolyte or coolant, as well as any entry ofoutside moisture can have catastrophic results. Specifically, not onlywill it cause the battery to operate in a less than optimal condition,the battery may completely fail. For industrial applications, andespecially when used as an emergency power supply, such batteries mustbe ready for immediate operation. If a battery fails, then it isincapable of providing power in an emergency. Thus, it is important toprovide early notification of a leak in such a battery.

[0007] Moreover, in the event of a failure, it is important to containany leaks, thereby precluding contamination of the battery by theleaking fluid. By limiting the contamination caused by the fluid leak,the battery can be more easily repaired and returned to operation.

[0008] Thus, it is an object of the invention to facilitate thecontainment of a leak within a flowing electrolyte battery.

[0009] It is a further object of the invention to facilitate thedetection of a leak of fluid within a flowing electrolyte battery.

SUMMARY OF THE INVENTION

[0010] The invention comprises a leak detection system for a flowingelectrolyte battery. The leak detection system comprises a containmentmember associated with at least one of a stack of a flowing electrolytebattery and an electrolyte reservoir of a flowing electrolyte battery,and, means for sensing a fluid leak within the containment member.

[0011] In a preferred embodiment, the sensing means comprises a switch,a controller and a connector. The switch includes a first plate and asecond plate. Fluid within the containment member (i.e. a leak) servesto electrically couple the first plate to the second plate, to, in turn,close the switch. The controller is associated with the switch, and, thecontroller is capable of sensing the condition of the switch. Theconnector is electrically associating the switch and the controller.

[0012] In such an embodiment, the sensing means further comprises aresistor positioned in parallel to the switch. In another suchembodiment, the at least one switch comprises a plurality of switchespositioned in parallel.

[0013] In a preferred embodiment, the containment member comprises astack leak containment member associated with at least one stack; and anelectrolyte reservoir leak containment member associated with at leastone reservoir. In one such embodiment, the sensing means is capable ofsensing a leak in each of the stack leak containment member and the atleast one electrolyte reservoir leak containment member.

[0014] In another aspect of the invention, the invention comprises amethod for detecting leaks in a flowing electrolyte battery. The methodcomprises the steps of (a) providing at least one containment member forat least one of the stack and the reservoir; (b) providing at least onesensor; (c) positioning at least one sensor such that a leak collectedin the at least one containment member triggers the sensor; (d)providing a controller; and (e) associating the controller with the atleast one sensor, such that the controller is capable of electricallycommunicating with the sensor.

[0015] In one embodiment, the step of providing at least one containmentmember comprises the steps of (a) providing a stack containment member;(b) positioning the stack containment member such that a leak from thestack is collected by the stack containment member; (c) providing areservoir containment member; and (d) positioning the reservoircontainment member such that a leak from the reservoir containmentmember is collected by the reservoir containment member.

[0016] In one embodiment, the step of providing a sensor comprises thesteps of (a) providing a sensor for the stack containment member; and(b) providing a sensor for the reservoir containment member. In such apreferred embodiment, the step of positioning the at least one sensorcomprises the steps of (a) positioning a sensor in the stack containmentmember such that a leak collected in the stack containment membertriggers the sensor; and (b) positioning a sensor in the reservoircontainment member such that a leak collected in the reservoircontainment member triggers the sensor.

[0017] In another embodiment, the method further includes the step ofsensing a fluid leak. Preferably, the method likewise includes the stepof determining the type of fluid leak

BRIEF DESCRIPTION OF THE DRAWINGS

[0018]FIG. 1 of the drawings is a schematic representation of thepresent invention;

[0019]FIG. 2 of the drawings is a schematic representation of the sensorof the present invention;

[0020]FIG. 3 of the drawings is a schematic representation of multiplesensors of the present invention; and

[0021]FIG. 4 of the drawings is a schematic representation of a secondembodiment of a sensor of the present invention

BEST MODE FOR PRACTICING THE INVENTION

[0022] While this invention is susceptible of embodiment in manydifferent forms, there is shown in the drawings and will be described indetail, one specific embodiment with the understanding that the presentdisclosure is to be considered as an exemplification of the principlesof the invention and is not intended to limit the invention to theembodiment illustrated.

[0023] Leak detection system 10 is shown in FIG. 1 as comprising stackleak containment member 12, electrolyte containment member 14 and means16 for sensing a leak. Leak detection system 10 is for use inassociation with a flowing electrolyte battery, such as zinc/brominebattery 100. While various flowing electrolyte batteries arecontemplated for use, the invention will be described with reference toa zinc/bromine battery solely as an example. Generally, zinc/brominebattery 100 includes one or more stacks, such as stack 102, electrolytereservoir 104, circulating means 106 and means 108 for controlling theclimate within battery 100. Stack 102 includes plurality of arrangedanodes and cathodes so as to comprise a plurality of stacked cells.Electrolyte reservoir 104 stores the electrolyte which is circulated bycirculation means 106 through stack 102. In certain embodiments, aclimate control means 108 may be incorporated to either heat or cool theelectrolyte so as to maintain the overall battery within operatingparameters.

[0024] Electrolyte stack containment member 12 is shown in FIG. 1 ascomprising base 30 and sides 32 which define cavity 34. As will beunderstood at least a portion of stack 102 is positioned within cavity34 such that, in the case of an electrolyte leak in stack 102, such aleak will fill cavity 34. In embodiments such as the embodiment shown inFIG. 1, wherein two vertically oriented stacks 102, 102′ form a tower,each stack has its own electrolyte containment member, 12, 12′. In suchan embodiment, the upper electrolyte containment member 12 includesoverflow opening 36, which, in turn, directs any overflow of electrolyteinto the electrolyte containment member 12′. In this manner, the spreadof electrolyte can be minimized.

[0025] Reservoir leak containment member 14 is shown in FIG. 1 ascomprising base 40 and sides 42 which define cavity 44. The electrolytereservoirs are positioned within the reservoir containment member suchthat any leak in the electrolyte reservoirs will be contained by thereservoir containment member. In addition, the reservoirs, and, in turn,the reservoir containment members are positioned below stack 102 suchthat, in the event of a leak which overflows electrolyte stackcontainment member 12 (or 12′) will be directed into, and contained by,reservoir containment member 14.

[0026] Sensing means 18 is shown in FIG. 1 as comprising sensor 50,controller 52 and connector 54. Sensor 50, as shown in FIG. 2, includesbase resistor 60 and switch 62. Switch 62 is in parallel with resistor60 and includes surface 70 and surface 72. As will be explained indetail below, in the event of a leak, the leaking fluid contacts surface70 and surface 72, to, in turn, close the circuit, essentially forming aswitch. While other shapes are contemplated, the surfaces 70, 72comprise mesh surfaces. Such mesh surfaces provide a relatively largesurface area for contact of the fluid with the mesh surfaces. Whilevarious systems are contemplated, resistor 60 comprises a resistorhaving a value of 3000 Ω, and the voltage applied to switch 62 andresistor 60 is 24V. Of course, various other circuits are contemplated,wherein the applied voltage may be either lower or higher, and, variousresistors are contemplated for use. In other embodiments, the resistormay be omitted wherein the controller views the circuit as an opencircuit until such time as the switch is closed.

[0027] Connector 54 connects controller 52 to sensor 50 such thatcontroller 52 is capable of sensing the closing of a switch 62 of sensor50. As will be explained below, if fluid from a leak provides a closedcircuit across surfaces 70, 72, then the resistance of the parallelcombination of the switch and the resistor effectively decreases, andthe current in the system increases (i.e. voltage remains constant, andtherefore voltage is equal to resistance times current). Controller 52comprises a digital microcontroller capable of reading the currentchange across the resistor and the switch. Of course, various analog ordigital systems are contemplated for use.

[0028] In operation, a flowing electrolyte battery is first equippedwith leak detection system 10. Specifically, stack leak containmentmember 12 is provided for each stack and each stack is positioned sothat a portion is within cavity 34. Additionally, electrolyte reservoirs104 are positioned within electrolyte reservoir leak containment member14.

[0029] Once the containment members are positioned, sensors 50 arepositioned within the cavity of each stack leak containment member.Subsequently, sensors are likewise positioned within the reservoir leakcontainment member, and likewise in the bottom of the unit (in case ofoverflow from any of the containment members). Once positioned, eachsensor is attached to one or more controllers, such as controller 52,via connectors 54. The sensors are positioned such that a leak thatcollects in any of the respective containment members (or at the bottomof the unit) will close a circuit about the surfaces 70, 72 of therespective switch 62, which can be sensed by controller 52. Generally,to achieve early recognition of leaks, the sensors are generallypositioned proximate the lowest point of the respective containmentmember.

[0030] From time to time, the flowing electrolyte battery can experiencean electrolyte leak in, for example stack 102. In such an instance, theelectrolyte leak will collect in the respective stack leak containmentmember 12. As the level of electrolyte in the stack leak containmentmember increases, eventually, electrolyte will contact both surface 70and surface 72 of switch 62, thereby effectively closing the circuit. Asa result, the current in the circuit will tend to increase, and theincrease is sensed by controller 50. Controller 50 can then provide sometype of final output (i.e. audible, visual, radio, infra red, connectionto a main control unit, etc.) so that a user can be informed of theleak.

[0031] Similarly, a leak in the reservoir will tend to cause electrolyteto enter into the reservoir containment member. As the level ofelectrolyte increases in the reservoir leak containment member,electrolyte will contact surface 70 and 72 of the sensor positionedwithin the reservoir leak containment member and the switch will beeffectively closed by the electrolyte. In turn, the circuit will exhibitan increased current which will be sensed by the controller.

[0032] It will be understood that in certain embodiments which utilize aliquid coolant, a coolant leak can occur. Such a coolant leak willgenerally collect in the base of the unit or in the reservoircontainment member. As with the electrolyte leak, as the coolant levelrises, the coolant will contact the surfaces 70 and 72 of one of thesensors, thereby effectively closing the switch.

[0033] Again, the controller will recognize the closing of the switch.Indeed, any fluid collection (i.e. electrolyte leak, coolant leak,condensation, outside precipitation) within any of the containmentmembers or proximate the base of the flowing electrolyte battery willtrigger a sensor switch to close. Since each such fluid generallycomprises a different resistivity (i.e. the electrolyte is generallyexhibits less electrical resistance than coolant orwater(contaminated)), current changes sensed by the controller will bedifferent based on the fluid that is causing the closing of therespective switch. In turn, the controller can be programmed todistinguish between the different leaks. In this case, if the controllerdetermines that the cause of the leak is condensation, there is no needto service the battery or to take the battery out of operation.

[0034] In another embodiment, as shown in FIG. 3, the sensor maycomprise a plurality of switches in parallel with a single resistor. Insuch an embodiment, each switch may be positioned in a different area,such as the electrolyte containment member, the electrolyte reservoircontainment member and the overflow area of the housing. As such, a leakin any one of these areas will cause fluid in the respective area toclose the switch, and in turn, lower the overall resistance of thecircuit. The lower resistance (and increased current) is then sensed bythe controller which is attached to the sensor. In such an embodiment,the controller can signal a leak, however, the precise location of theleak is not known.

[0035] In another embodiment, as shown in FIG. 4, sensor 50 may includean additional switch, namely, switch 63 which is positioned in parallelto switch 62 and resistor 60. When installed, switch 63 is positionedlower than switch 62 such that a leak will first close switch 63 beforethe leak closes switch 62. As will be understood, a small leak will tendto close switch 62, whereas a large leak will tend to close switch 63and switch 62. As a result, the controller will receive a first currentreading increase as the leak closes switch 63 and a second currentreading increase as the leak closes switch 62. Accordingly, thecontroller can be used to access the severity of the leak.

[0036] The foregoing description merely explains and illustrates theinvention and the invention is not limited thereto except insofar as theappended claims are so limited, as those skilled in the art who have thedisclosure before them will be able to make modifications withoutdeparting from the scope of the invention.

What is claimed is:
 1. A leak detection system for a flowing electrolytebattery comprising: at least one containment member associated with atleast one of a stack of a flowing electrolyte battery and an electrolytereservoir of a flowing electrolyte battery; and means for sensing afluid leak within the containment member.
 2. The system of claim 1wherein the sensing means comprises: at least one switch comprising afirst plate and a second plate, wherein fluid within the containmentmember serves to electrically couple the first plate to the secondplate, to, in turn, close the switch; a controller associated with theswitch, the controller capable of sensing the condition of the switch;and a connector electrically associating the switch and the controller.3. The system of claim 2 wherein the sensing means further comprises: aresistor positioned in parallel to the switch.
 4. The system of claim 2wherein the at least one switch comprises a plurality of switchespositioned in parallel.
 5. The system of claim 1 wherein the at leastone containment member comprises: at least one stack leak containmentmember associated with at least one stack; and at least one electrolytereservoir leak containment member associated with at least onereservoir.
 6. The system of claim 5 wherein the sensing means is capableof sensing a leak in each of the stack leak containment member and theat least one electrolyte reservoir leak containment member.
 7. A leakdetection system for a flowing electrolyte battery comprising: at leastone containment member associated with at least one of a stack of aflowing electrolyte battery; at least one containment member associatedwith an electrolyte reservoir of a flowing electrolyte battery; andmeans for sensing a fluid leak within one of the containment members,wherein the sensing means comprises: at least one sensor having at leastone switch positioned within one of the containment members such that aleak collecting in the respective containment member triggers theswitch; at least one controller associated with the sensor; and aconnector associated with each of the sensor and controller.
 8. The leakdetection system of claim 7 wherein the sensor includes a plurality ofswitches;
 9. The leak detection system of claim 8 wherein the pluralityof switches are positioned substantially in parallel.
 10. The leakdetection system of claim 7 wherein the sensor includes at least oneresistor positioned in parallel with the at least one switch.
 11. Theleak detection system of claim 7 wherein the controller includes a meansfor signaling the condition of the sensor to a user.
 12. A method fordetecting leaks in a flowing electrolyte battery comprising the stepsof: providing at least one containment member for at least one of thestack and the reservoir; providing at least one sensor; positioning atleast one sensor such that a leak collected in the at least onecontainment member triggers the sensor; providing a controller; andassociating the controller with the at least one sensor, such that thecontroller is capable of electrically communicating with the sensor. 13.The method of claim 12 wherein the step of providing at least onecontainment member comprises the steps of: providing a stack containmentmember; positioning the stack containment member such that a leak fromthe stack is collected by the stack containment member; providing areservoir containment member; and positioning the reservoir containmentmember such that a leak from the reservoir containment member iscollected by the reservoir containment member.
 14. The method of claim13 wherein the step of providing a sensor comprises the steps of:providing a sensor for the stack containment member; and providing asensor for the reservoir containment member.
 15. The method of claim 14wherein the step of positioning the at least one sensor comprises thesteps of: positioning a sensor in the stack containment member such thata leak collected in the stack containment member triggers the sensor;and positioning a sensor in the reservoir containment member such that aleak collected in the reservoir containment member triggers the sensor.16. The method of claim 12 further comprising the step of sensing afluid leak.
 17. The method of claim 16 further comprising the step ofdetermining the type of fluid leak.